Stephen Hawking said yesterday that Earth could become an inhospitable, sweltering hothouse like Venus, which sometime in its past underwent a phase of runaway greenhouse effects.

That’s a pretty dramatic claim. And though you can read about it all over the place today, it is not news.

Six years ago Hawking made the same “Earth will become like Venus” comment.

Thing is, science has yet to determine just how plausible that scenario is, and such an extreme proposition perhaps ought to be supported by data rather than just tossed out as a sound bite. It is the sort of hype that could have just the opposite effect he might have intended, giving ammunition for those who say climate change research is a field of alarmists, thereby pulling the public’s attention away from real data about change that is underway (including today’s announcement that Earth hit a 400-year temperature high).
Meanwhile, Hawking’s doomsday predictions are becoming routine.

In 2001, he said threats of bioterrorism had him worried that humans would not survive the next 1,000 years unless—and this is his underlying proposition for avoiding both of his doomsday predictions—we leave the planet. (He reiterated that notion earlier this month.)

As exciting as space travel and colonization sounds, getting there is years if not decades away, and there is a danger in Hawking’s logic, or at least the way he presents it. It suggests we don’t need to clean up after ourselves because we’re leaving soon anyway. For now, I’d rather we all keep our feet on the ground and tidy up a bit.